Shared hosting
Shared hosting
Shared (or Virtual) web hosting
A few things about shared hosting
Shared hosting means that the same server (computer) hosts more than a single website, the actual number of hosted websites depending on their size and number of visitors (total occupied space, total monthly bandwidth and used server resources).
With the powerful processors of today, it's not at all unusual to find hundreds of websites hosted on a single server. As I explained in another article, this is not a problem in itself.
The best thing about Shared or Virtual hosting is that it allows individuals and businesses with limited financial resources to establish an online presence with almost all the bells an whistles associated with a dedicated server.
The price for a shared hosting account however, is low compared to the dedicated server solution. It can even be in some instances very low! Generally those are the times when you have to be careful.
Problems that are common in a shared hosting environment:
1. Overcrowded servers
This problem is one of the most common in the web hosting industry (in the shared hosting section of it). It's not a shared hosting inherent problem though. It usually has to do with poor server resources management, poor business planning and reactive-type of behavior from the part of the hosting company -- instead of proactive behavior.
This problem is one of the first that have to be addressed when shopping for
hosting. As long as the customer (that's you! 
) shops around and knows what to
look for and -- just as importantly -- what to look out for, everything should
be OK. (Hint: to learn how to find a reliable host, I suggest you to read most
of the articles I wrote and posted on this website.)
2. Security issues
In a perfect world, all a web hosting company would need to do would be to connect the server to the Internet and keep things running smoothly on the server. The Internet is not exactly a peaceful place though. There are all kinds of internet "terrorists". They're sometimes called hackers, sometimes they're called crackers. It doesn't matter how you call them. The important thing is that they're out there and that they make the life of every decent hosting business harder than it should be.
Hackers and crackers are extreme cases however. On the 'net, regular people behave in a different manner than in real life. When hundreds of people have access to a computer (the server) there are real chances to find that one of them is... less than honest.
Added to that, in a shared hosting environment it's not that uncommon to find that you can easily access other people's accounts (a shared hosting account is basically a directory (folder) on a server's hard disk). Fortunately this is usually not something critical, as in most cases what you store on the server is meant to be visible to the public anyway.
There are though lots of things that you have to keep secret. For example, if you're selling software, you cannot afford such "leaks". If you have a newsletter and you store the email addresses of your subscribers on the server as plain text files, you definitely don't want them to get in the wrong hands. There are lots of other examples, these are just some of the obvious ones.
Generally, a server used to host more websites is usually not as secure as a dedicated server. There's usually a trade-off between security and freedom, just as in real life.
3. Neighborhood related problems
The - what I call - "neighborhood problems" are complex issues, all having a common trait: they all involve what the other people are doing on that server. Those people (and their websites) are your closest online neighbors and they're just as important as your real-life neighbors are.
If one of those neighbors is using the account to test new scripts (and he's really bad at coding) then you (and everybody on that server) risks that one day, one of those badly written scripts might crash the server. That means at least a couple of minutes of downtime.
One of your "neighbors" might be the curious type. If it also happens that he has the necessary knowledge, he might be able to get access to the files in your account. That's like someone searching though your entire house. It might be just out of curiosity, but is that really an excuse?
There is also another important neighborhood related thing that has to do more with the inner workings of the Internet than with people. Chances are that your site is sharing the IP with a number of other sites. Now, if a spammer happens to find a temporary home on that server, the IP where the spam originates from might be listed in a spam list and this can lead to your emails not being received by servers throughout the web.
A simple solution might seem to ask for an IP of your own. Unfortunately some hosts don't offer this option. Others ask for a monthly fee for each IP, usually about $2 per month. There are still others who will give you a dedicated IP from the start. That doesn't mean that you don't pay for it though. The price of the package might be a little bit higher because this option enabled by default.
However, a dedicated IP doesn't solve the emails problem because while your website will indeed have an IP of its own, the emails will still be relayed through a single, shared IP.
Another issue is represented by adult hosting. Depending on your views and beliefs, you might want to make sure that your site doesn't share space with adult sites. On the other side, if your site is adult in nature, you should make sure that the host accepts such content on its servers.
Advantages:
The first advantage is the low price, which I already told you about in the beginning of this article. The second advantage (which most web hosting customers don't even fully realize) is that the client doesn't have to manage the server. Managing a server is a complicated job, done by professionals. Hiring someone for this job is not a feasible thing to do for most website owners.
For most people shared hosting is the pretty much the only feasible choice. That's why most don't even think of or have never heard of other types of hosting. For most people shared hosting is the hosting and things will remain like this for a long while I think.
Conclusions:
No matter what the disadvantages are, it's clear that the shared hosting solution is here to stay. The vast majority of websites today use shared hosting and the reason is obvious: it's advantages overweight its disadvantages. Unless your website is so big that it really needs the computing power and the space offered by an entire server, shared hosting is most likely to be right the solution for you too.